The primary objective of this proposal is to complete an analysis of the pattern of variations in the prevalence of cause of hospitalization and of surgical or medical procedures among small areas in Maine, Rhode Island and Vermont. Previous work shows that specific admissions and/or treatments have characteristic variations: the prevalence rates for cancer treatments, hip fractures and inguinal hernial procedures vary much less than do those for hysterectomies, prostatectomies and tonsillectomies. Further, for high variation procedures, variations in per capita costs are related much more strongly to variations in admissions per capita than to variations in average length of stay or average cost per case. This research generalizes the investigation of patterns of variation to include the entire hospitalized case mix. Much of the background work necessary to complete this research was done under a grant from the Health Care Financing Administration, which, was terminated at the beginning of the final year of a five year grant period. To date, we have assembled a multi-year data-base covering Maine, Rhode Island and Vermont; encoded basic ICDA and H-ICDA rubrics into case-mix classifications based on DRG, PAS-A and PAS-B and into our own, more clinically oriented groupings; developed computer software to undertake the rate analyses; developed new statistical tools for measuring variation; and applied these to develop a descriptive epidemiology of the use of common surgical procedures. For two surgical subspecialties, urology and orthopedics, we have started a systematic investigation of hospitalized case-mix and surgical treatments undertaken by the specialty. This grant will enable us to bring this interrupted research to completion.